1. Field of the Invention
The present invention relates to a sealing device and more particularly to an unidirectional sealing device which ensures fluid tightness between a cylindrical member and a cylindrical bore into which said cylindrical member is to be fitted.
2. Description of the Prior Art
A conventional sealing device required for sealing a clearance between a cylindrical member such as piston or the like and a cylindrical bore such as cylinder or the like is constructed such that an annular seal ring with a slit formed at a certain position therearound is fitted around an annular seal groove on the outer surface of the cylindrical member in such a manner that the seal ring comes in resilient contact with the inner wall of the cylindrical bore due to expansive force of the piston ring itself or with the aid of another resilient member. However, it is pointed out as drawbacks inherent to the conventional sealing device of the above-described type that gas or liquid may be leaked through the slit on the seal ring and furhter the conventional sealing device requires in its manufacturing process additional work such as lathing, grinding finish and the like on both the inner and outer peripheries of the seal ring, thus increasing the cost.